Localised delivery of therapeutic agents to CNS malignancies: old and new approaches

Despite advances in neuro-imaging, neurosurgery, radiation therapy, and chemotherapy, limited progress has been made in the treatment of patients with high-grade astrocytomas. Primary brain tumours are considered to be among the most difficult neoplasms to treat which is largely due to the invasive nature of these tumours and the complexity of the organ in which they arise. In an attempt to overcome some of the limitations of systemic delivery of anticancer drugs, several methods of localised delivery have been developed. In this article we briefly review some of the current literature on systems for localised delivery of therapeutic agents to brain tumors, which consists of osmotic mini-pumps, infusion pumps (convection-enhanced delivery), and cell grafting. Furthermore, special emphasis is made on bio-degradable polymers, which is at present the best characterised system of local delivery to brain tumors, along with a promising novel delivery system, based on non-degradable polymer encapsulated cell therapy.